Plasma purifying devices that carry out plasma purification therapy such as separation of plasma components of plasma adsorption have a collected blood circuit, a return blood circuit, a plasma circuit, a plasma separator and a plasma component separator or plasma adsorber. Following completion of plasma component separation or plasma adsorption, blood remains in the collected blood circuit, the return blood circuit and blood side space of the plasma separator, and plasma remains in the filtration side space of the plasma separator, the plasma circuit, and the plasma component separator or plasma adsorber. Since the blood and plasma remaining in the above-mentioned circuits, the plasma separator and the plasma component separator or plasma adsorber are useful components, they are typically returned to the patient following plasma purification therapy. However, since plasma purification therapy uses not only a plasma separator, but also a plasma component separator or plasma adsorber, the overall device is complex and requires an extremely complex operation such as adjusting flow rates, driving and stopping of a blood pump and plasma pump, or opening and closing blood circuits and plasma circuits using Pean hemostatic forceps and the like. Therefore, methods for easily recovering blood and plasma have been proposed as in Patent Document 1 and Patent Document 2. Both of these publications disclose a method for automatically recovering blood and plasma by switching the operations of various valves and pumps using pressure and cumulative operating amounts of pumps.
FIG. 3 shows an example of the configuration of a plasma component separation device 50 as an embodiment of Patent Document 1.
The plasma component separation device 50 has a plasma separator 5 and a plasma component separator 6a. A collected blood circuit 1 is connected to a blood inlet of the plasma separator 5, and a blood pump 7 is arranged in the collected blood circuit 1. First pressure measuring means 10 is arranged between the blood pump 7 and the plasma separator 5. A return blood circuit 2 is connected to the blood outlet of the plasma separator 5, and second pressure measuring means 11 is arranged in the return blood circuit 2. A first pressure measurement circuit 3 is connected to a first filtration outlet of the plasma separator 5, a plasma circuit 4 is connected to a second filtration outlet, the plasma circuit 4 is connected to the plasma component separator 6a, and a blood pump 8 is arranged in the plasma circuit 4. Third pressure measuring means 12 and a branch line are arranged in the first pressure measurement circuit 3, and a second valve 21 is arranged in the branch line. A return plasma circuit 15 is connected to a first plasma component outlet of the plasma component separator 6a. The return plasma circuit 15 is connected to the return blood circuit 2, and a first valve 20 is arranged upstream from the junction of the return plasma circuit 15 and the return blood circuit 2. The plasma component separation device 50 further has an arithmetic processing unit 30 and a control unit 31. The arithmetic processing unit 30 and the control unit 31 are connected, and arithmetic processing unit 30 is connected to the first pressure measuring means 10, the second pressure measuring means 11, and the third pressure measuring means 12, while the control unit 31 is connected to the blood pump 7, the plasma pump 8, the first valve 20 and the second valve 21.
The above provides a description of the overall configuration of the blood component separation device 50 of Patent Document 1. Next, an explanation is provided of the operating method of the plasma component separation device 50 for recovering blood and plasma following completion of plasma purification therapy.
In the state following completion of plasma purification, the collected blood circuit 1, the return blood circuit 2 and the blood side space of the plasma separator 5 are filled with blood. In addition, the filtration side space of the plasma separator 5, the plasma circuit 4, the plasma component separator 6a and the return plasma circuit 15 are filled with plasma. At this time, since the collected blood circuit 1 and the return blood circuit 2 are still connected to the patient, and the blood pump 7 is still operating, the blood pump 7 is temporarily stopped, and the collected blood circuit 1 is disconnected from the patient and connected to physiological saline for recovery.
Once the collected blood circuit 1 has been connected to the physiological saline for recovery, operation of the blood pump 7 is resumed and blood is recovered from the collected blood circuit 1, the plasma separator 5 and the return blood circuit 2. At this time, since the plasma pump 8 is stopped with the filtration side space of the plasma separator 5, the plasma circuit 4, the plasma component separator 6a and the return plasma circuit 15 still filled with plasma, there is the risk of the plasma coagulating if an excessive amount of time is required to recover the blood.
Next, the blood pump 7 is stopped, the first valve 20 is closed, the second valve 21 is opened and the plasma pump 8 is operated to recover plasma from the filtration side space of the plasma separator 5, the plasma circuit 4, the plasma component separator 6a and the return plasma circuit 15. Since the blood pump 7 is stopped at this time, there is the risk of blood coagulation is blood has not been recovered as previously described. Once recovery of plasma has been completed, the return blood circuit is disconnected from the patient.
As has been described above, in this recovery method, since the plasma pump 8 is stopped during recovery of blood, clogging may occur in the plasma component separator 6a or a plasma adsorber 6b thereby preventing subsequent recovery of plasma even if the plasma pump 8 is operated. In addition, even if plasma is recovered first followed by recovery of blood, since the blood pump 7 is stopped during recovery of plasma, there is the risk of blood coagulating in the collected blood circuit 1, the return blood circuit 2 and the blood side space of the plasma separator 5.
Moreover, during recovery of blood, there is the disadvantage of handling of work having to be performed by two people consisting of a person who handles the patient after disconnecting the collected blood circuit or return blood circuit from the site where connected to the patient, and a person who handles the plasma purifying device. Namely, work performed by two persons begins when the collected blood circuit is disconnected from the patient, and ends when all recovery work has been completed and the return blood path is disconnected from the patient.
Since the flow rate of a blood pump is typically about 100 mL/min, and the amount of blood remaining in the collected blood circuit, the return blood circuit and the blood side space of the plasma separator is about 200 mL, blood recovery is completed in about 2 minutes. On the other hand, since the plasma component separator or plasma adsorber can become clogged if the flow rate of the plasma pump is excessively high, it is typically amount 20 mL/min. Since amount 200 mL of plasma remain in the filtration side space of the plasma separator, the plasma circuit and the plasma component separator or plasma adsorber, it ends up taking about 10 minutes to recover plasma. Consequently, this results in the disadvantage of prolonging the amount of time required for the work performed by two persons.